Crumble the fresh yeast into the bowl of a stand mixer or a large bowl if you’re working by hand. Stir in a little bit of the cold milk until the yeast has dissolved. If using active dry yeast, I just threw in the same amount as the fresh.
Add the rest of the milk, sugar, freshly ground cardamom and egg and stir. Combine flour and baking powder in a medium bowl. Add about half of the flour & baking powder mix to the dough, then stir until the dough just comes together.
Add the salt, the remaining flour mix and the butter. Work the dough using the dough hook on a stand mixer, for 10-15 minutes or until the dough is very soft and elastic. The dough will be a little sticky but don’t be tempted to add more flour! Cover the bowl with a kitchen towel and let the dough rest for 10 minutes.
On a floured surface, divide the dough into 9 equally sized pieces. Using your hands (which should also be floured), shape each piece of dough into a ball using a circling motion until the bun is smooth and shiny. Cup your hand around the bun without too much pressure and swirl it around in a circling motion to shape it into a round and smooth ball. Ensure that when creating these balls, if there are any crevices avoid using those on top. You want a smooth top.
Gently transfer the buns to a baking sheet with baking paper, and remember to leave some space between them so they can rise. Cover the buns with a clean kitchen towel and leave to rise for 60-90 minutes. Meanwhile, go through the next steps to prepare the Nutella filling.